Complex esters produced by reacting a dicarboxylic acid,a polyhydric alcohol and boric acid



United States Patent 3,544,614 COMPLEX ESTERS PRODUCED BY REACTING A DICARBOXYLIC ACID, A POLYHYDRIC ALCO- HOL AND BORIC ACID Norbert C. Schwartz, Homer, N.Y., assignor to R. H. Miller Company, Inc., Homer, N.Y., a corporation of New Jersey No Drawing. Filed June 8, 1967, Ser. No. 644,497 Int. Cl. C07f /04, 9/08 US. Cl. 260462 6 Claims ABSTRACT OF THE DISCLOSURE Complex esters for use as lubricants and to impart desirable rust inhibiting films on metallic surfaces, such as those of wire, rods, strips, webs and plates, by way of example, as produced by compositions of matter composed of various combinations of diand poly-basic carboxylic acids, polyhydric alcohols, borates and phosphates, particularly in the equivalent Weight ratios set out in the specification.

This invention relates to the production and use of complex esters and more particularly to the production and use of complex esters which may be employed, for example, as lubricants for metallic surfaces and which lubricants have dual functions since they possess rustinhibiting characteristics.

The complex esters of this invention are produced by various combinations of dior polybasic carboxylic acids, polyhydric alcohols, borates and phosphates.

Normal dibasic esters commonly employed as lubricants suffer from the disadvantages of lacking rust-inhibiting properties.

An important object of this invention is to provide lubricants for metallic surfaces containing complex esters synthesized from compositions of matter including, for example, boric acid, which lubricants actually impart rust inhibiting properties to films of the lubricants spread upon the surfaces of the metals.

Lubricants for metallic surfaces, which lubricants in- "ice clude synthetic esters produced by the employment of some acids, sometime contain additives, which have no part in the synthesizing of the esters and have no lubrieating characteristics but are rust or corrosion inhibitors, pure and simple.

Another important object of this invention is to provide complex ester-containing lubricants with the dual function of inhibiting formation of rust. These esters are synthesized from at least one constituent which would be regarded generally as not suitable for rust inhibiting purposes, and may actually be regarded as having corrosive properties. However, when employed as detailed herein, the resulting complex esters do inhibit formation of rust.

Other objects and advantages of the invention will be apparent during the course of the following detailed description of the invention.

In this disclosure, new, unique, and useful complex esters have been prepared by combining, for example:

(a) Boric acid, a polyhydroxylic alcohol, and a saturated or unsaturated aliphatic dicarboxylic acid or anhydride.

(b) Boric acid, a polyhydroxylic alcohol, and an aromatic dicarboxylic acid or anhydride.

(c) Boric acid, an alkylolamine, and a saturated or unsaturated aliphatic dicarboxylic acid or anhydride.

((1) Orthophosphoric acid, a polyhydroxylic alcohol, and a saturated or unsaturated aliphatic dicarboxylic acid or anhydride.

(e) Orthophosphoric acid, a polyhydroxylic alcohol, and an aromatic dicarboxylic acid or anhydride.

The polyhydroxylic alcohols include the glycols, triols, tetrols, and hexols, and encompass the entire general family of polyhydroxylic alcohols. The concepts of (a), (b), (c), (d), and (e) in the preceding paragraphs apply to the entire family of polyhydroxylic alcohols and are not limited to these examples specifically cited. Among the particularly suitable specific polyhydroxylic alcohols are glycerin ethylene glycol, hexylene glycol, polyethylene glycols, pentaerythritol, sorbitol, and 2,4, 7,9-tetrarnethyl-5-decyne-4, 7-diol.

Typical examples of formulations for the preparation of new, unique and useful complex esters of this invention are as follows:

Hours Acid Acid We1ght, Mole heated value value Example Starting ingredients grams ratio at 110 C. calc. observed Boric acid 22. 8 1. 00 I Glycerin. U.S.P 69.0 1. 96 300 200 125 Sebacic acid 146. 0 1. 89 22. 8 1. 00 II 69. 0 1. 96

136. 0 1. Boric acid. 22.8 1. In Glycerin, U.S.P 69. 0 1.

Azelaic acid, 68.0 0. 98 Phthalic acid 60.0 1. 10 Boric acid 30. 2 1. 00 IV Glycerin, U S P- 92.0 2. 05

Phthalic anhydrid 89. 0 1. 10 Be1'icacid 20.0 1.00 V Ethylene glycol. 62.0 3. 09 Azelaic acid 90. 0 1. 48 Boric acid- 20. O 1.00 VI Hexylene glycol 88. 6 3. 09 Azelaic aicd 94. 0 1. 54 Boric acid 30. 9 1. 00 VII Pentaerythritol 136.00 2.00 Sabacic acid 100.00 1.00 Boric acid 12. 5 1.00 VIII Solbitol. 85. 0 1. 62

"" Azelaic acid 50.0 1. 31

Phthalic acid 40. 0 1. 33 phosphoric acid 19. 0 1.00 IX. 200 MW polyethlcne glycol- 110. 0 3. 00 Phthalic anhydridc 46. 0 1. 50 85% phosphoric acid 43. 3 1.00 X Glycerin, U.S.P 69. 0 2.00 Azelaic acid 68.0 0.96 Plithalic anhydr 60. 0 O. 96

Hours Acid Weight, Mole heated value Example Starting ingredients grams ratio at 110 C. ealc.

Acid value observed Diethanolamine Azelaic acid Boric acid XII Triethanolamino Azolaic acid.

B oric acid XI Boric acid- XIIL Glycerin, U.S.

Maleic anhydride Boric acid XIV Surfynol 475- Sebaeic acid The above-named ingredients may be introduced to a rotary-blades mixer and thoroughly mixed together, or otherwise thoroughly mixed together in any conventional way.

The 60% sorbitol of Example VIII is an aqueous solution of 60% by weight sorbitol and 40% by weight water; the phosphoric acid of Example X is an aqueous solution of 85% by weight phosphoric acid and by weight water; and the Surfynol 475, is an ethoxylated 2,4,7,9-tetramethyl-5-decyne-4,7 diol containing 75% by weight ethylene oxide and by weight 2,4,7,9-tetramethyl-5-decyne-4, 7-diol.

As for the complex esters of this invention, the present invention is in no way limited by any theory concerning the structure of the complex esters thereof and the exact nature of the over-all reactions are not entirely known; in general, the structural aspects may be tentatively summarized as follows, by referring to one fundamental monomeric unit. As the esters polymerize, a plurality of these units are joined together with each other or with incompletely formed partial units. The fundamental unit is:

n* being the number of monomeric groups in the polymer, in which:

X is a boric acid or phosphoric acid radical which may contain one or two unsubstituted hydrogens.

Y is a polyhydroxylic alcohol radical which may contain between zero and five unreacted hydroxyl function groups. Y may also be a triethanolamine or diethanolamine radical in which there are one or two unreacted hydroxyl groups.

Z is a saturated or unsaturated aliphatic dicarboxylic acid radical containing four to twenty-four carbon atoms. Z may also be the phthalate radical.

n and n' are the number of moles of Y radicals present. It or 11' may be zero. In the present invention, the sum of n plus 11 is preferably between 0.4 and 6.0.

n" and n' are the number of moles of Z radicals present. 11 or 11" may be zero. In the present invention, the sum of it plus it" is preferably between 0.4 and 2.7.

A couple of examples of simple polymers may be represented as:

(The symbols m, m, and m" are used to indicate that the quantities may be diflerent from n, n, and n.)

With the above tentative summary in view, a generalized structural composition and mole ratios of examples as above are summarized in the following table:

Numb er of equivalents of carboxylic acid These concepts encompass the complete family of dicarboxylic acids and the concepts are not limited to these examples specifically cited.

In addition to the acids named in the above examples, I have experimented with other related acids such as: oxalic, malonic, succinic, glutaric, adipic, pimelic and suberic.

A number of tests were run in connection with the rust-inhibiting characteristics of the lubricants of this invention. These included outdoor exposure of 1 /2 x 2 inch cold rolled l8-gauge mild steel panels coated with a solution of 0.05% ester of this invention in isopropyl alcohol. Exposure to air and rain disclosed only slight rusting over a period of a months exposure, while a like panel, similarly exposed, but uncoated, typically started rusting in one day and was badly rusted in about four days. As a further test, a lubricant of this invention was used as a wire-drawing lubricant to draw bright basic wire in two holes from inch rod down to 0.2437 inch. Exposed to the air, snow and rain, and compared with a like sample containing a lubricating film of approximately 20% potassium oleate, 5% lime and the balance water, the first-named wire had scattered areas of slight rusting at the end of a period from mid-November to mid-December, while the second-named wire had rust areas after three days and a uniform coating of light rust at the ned of the same test period and under similar exposure conditions. In another test, cold-rolled carbon steel panels were highly polished, cleaned with distilled water, alcohol and Freon TF. They were then quickly dipped into a fluidized sample of selected lubricant and allowed to drain. The samples were then placed in a humidity cabinet maintained at F. and 95% relative himidity. The samples were periodically observed and,

when significant corrosion appeared, they were removed. The lubricants of this invention showed no rusting of significance until an elapse of 72 hours while the panels coated with a conventional lubricant showed rusting after 48 hours. With the humidity cabinet maintained at 140 F. and 95% relative humidity like panels were tested. The panels containing lubricants of this invention showed first rusting at 84 hours while those containing conventional lubricants, showed first corrosion at 34 hours. The tests employing the humidity cabinet were carried out essentially the same as that of the American Society for Testing Materials Methods (Method No. D- 1748 Rust Preventative Evaluation in the Humidity Cabinet).

What is claimed is:

1. Complex esters obtained by reacting at at least about 110 C. for about 150 to about 300 hours, an aliphatic dibasic carboxylic acid or its anhydride, a polyhydric alcohol, and boric acid, said dibasic acid being an acid or anhydride selected from the group consisting of sebacic, azelaic, phthalic, maleic, oxalic, malonic, succinic, glutaric, adipic, pimelic, and suberic, said polyhydric alcohol being selected from the group consisting of glycerin, ethylene glycol, hexylene glycol, pentaaerythritol, sorbitol, polyethylene glycol, having a molecular weight of about 200, and ethoxylated 2,4,7,9-tetramethyl-S-decyne-4,7-diol containing about 75% by weight ethylene oxide and 25% by weight 2,4,7,9-tetramethyl-5-decyne-4,7-diol, said mole ratio of acid and alcohol per mole of boric acid being from about 1.0 to 2.6 and 0.6 to 3.0, respectively.

2. The composition of claim 1 where the acid is sebacic and the alcohol is glycerin.

3. The composition of claim 1 where the acid is azelaic and the alcohol is glycerin.

4. The composition of claim 1 where the acid is a mixture of azelaic and phthalic and the alcohol is glycerin.

5. The composition of claim 1 where the acid is azelaic and the alcohol is ethylene glycol.

6. The composition of claim 1 where the acid is maleic and the alcohol is glycerin.

References Cited UNITED STATES PATENTS 2,189,833 2/1940 Rosenblum 260-462 X 3,202,693 8/1965 Gaertner 260-978 X CHARLES B. PARKER, Primary Examiner A. H. SUTTO, Assistant Examiner U.S. Cl. X.R. 

